Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1985 Molecular Studies of Thamnophiine Snakes. Robin Lawson Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Lawson, Robin, "Molecular Studies of Thamnophiine Snakes." (1985). LSU Historical Dissertations and Theses. 4058. https://digitalcommons.lsu.edu/gradschool_disstheses/4058 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This reproduction was made from a copy of a document sent to us for microfilming. 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Zeeb Road Ann Arbor, Ml 48106 8517741 Lawson, Robin MOLECULAR STUDIES OF THAMNOPHIINE SNAKES The Louisiana State University and Agricultural and Mechanical Col. Ph.D. 1985 University Microfilms International 300 N. Zeeb Road, Ann Arbor, Ml 48106 PLEASE NOTE: In all cases this material has been filmed In the best possible way from the available copy. Problems encountered with this document have been identified herewith a check mark V . 1. Glossy photographs or pages ______ 2. Colored illustrations, paper or print _______ 3. Photographs with dark background _____ 4. Illustrations are poor copy _______ 5. Pages with black marks, not original copy ______ 6. Print shows through as there is text on both sides of p ag e _______ 7. Indistinct, broken or small print on several pages / 8. Print exceeds margin requirements ______ 9. Tightly bound copy with print lost in spine________ 10. Computer printout pages with indistinct print _______ 11. Page(s) ____________lacking when material received, and not available from school or author. 12. Page{s) ____________seem to be missing in numbering only as text follows. 13. Two pages numbered . Text follows, 14. Curling and wrinkled pages ______ 15. Dissertation contains pages with print at a slant, filmed as received __________ 16. Other____________ ______________________________________________________ University Microfilms International MOLECULAR STUDIES OF THAMNOPHIINE SNAKES A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College In partial fulfillment of the ■requirements for the degree of Doctor of Philosophy in The Department of Zoology and Physiology by Robin Lawson B.S., California State University, Hayward, 1976 M.A,, California State University, Hayward, 1978 May 1985 ACKNOWLEDGEMENTS To my major professor, Douglas A. Rossman, and my committee members, Herbert C. Dessauer, Mark S. Hafner, James S. Rogers, Walter J, Harman, Valentine Lance, and Nikolaus H. Fischer I am indebted for their encouragement and friendship during the course of this study. The large number of live specimens which this study required could not have been obtained without the assistance of many individuals. The following persons have provided me with specimens, J. S. Applegarth, S. J. Arnold, R. W. Axtell, J. Berducci, J. M. Bishop, W. Birkhead, R. M. Blaney, R. C. Bothner, R. A. Brandon, M. J. Braun, E. D. Brodie Jr., T. L. Brown, J. A. Campbell, J. D. Camper, S. W. Cardiff, R. Claire, C. J. Cole, T, Coulson, D. L. Cundall, L. D. Densmore 111, W, W. Dimmick, H. A. Dundee, M. Ellerman, J. M. Fitzsimons, N. B. Ford, M. Freed, P. Freed, R. S. Funk, R. A. Gibson, S. J. Godley, B. G. Hanks, P. Gregory, G. Hanson, D. R. Hart, M. Hever, J. B. Iverson, M. Jennings, G. Keasler, Q. Kinler,.C. P. Kofron, F. Kraus, G, Kuehnhanss, V, Lance, L, A. Landry, B. K. Lawson, S. M. Lawson, J. Lewis, C. S. Lieb, E. A. Liner, C. J. McCoy, M. McLaughlin, J. S. McLean, P. Meylan, M. Mitchell, K. A. Morris, R. W, Murohv, H. R. Mushinsky, M. Nickerson, G. 1. Owen, L. Porras, A. Resetar, M. B. Robbins, M. A. Romano, P. Rosen, D. A. Rossman, W. E. Sanderson, R. A. Sajdak, P. Sattler, T. D. Schwaner, G. W. Schuett, N, L. Scott, P. E. Scott, J. F. Scudday, L. M. Scudder, W. L. Shoop, C. Smith, H. M. Smith, L. Spayde, G, R. Stewart, B. Strand, B. D. Taubert, S. R. Telford Jr., R. Thomas, J. K. Tucker, R. H. Vaeth, M. D. Williams, H. Windgassen, and the late C. Yates. 1 am especially grateful to my good friends Philip G. Frank, Albert J. ii Meier, and Jeffrey A. Cole who have always been prepared to accompany me in the field, and whose collecting expertise is unexcelled, 1 am grateful to M. S. Hafner and H. C. Dessauer for the free use of their laboratories. Some specimens were collected under permits from the Texas Parks and Wildlife Department, and the Direccion General de Fauna Silvestre, Mexico, D. F . , Mexico. My greatest debt is to my wife, Betsy, who has endured long periods of separation and who has capably managed our household alone. Without her continuous affection, encouragement and support this work could not have been completed and to her it is dedicated. iii TABLE OF CONTENTS ACKNOWLEDGMENTS.............................................-..... ii ABSTRACT............................................................ PART 1. The population structure of Nerodia fasciata and Nerodia clarkii........................................... 1 Introduction........................................ .......2 Methods................................. 7 Allocation of specimens to subspecies................. 8 Electrophoretic methods......................... ......10 Methods of data analysis.............................. 11 Results....................................................18 Discussion................................................ 24 Differentiation in the freshwater group..............24 Differentiation in the saltwater group...............29 Differentiation between the freshwater and saltwater groups....................................30 Evidence from the Chokoloskee Island, Teal Lake, and Boca Ciega populations.............33 The fate of the hybrid populations................... 36 Evolution and taxonomy............................. ...38 Summary.............. 43 Captions for figures......................................44 Figures................... 46 Tables........ 33 Literature Cited...................... 62 Acknowledgments...................................... .....72 PART 2. Intergeneric relationships........... 73 Introduction. .......................................... 74 Materials and Methods .................. 75 Results................. 77 Di scussion............. .81 Analysis of electrophoretic data in systematics......................................81 Evaluation of relationships among thamnophiine genera.................. 83 Taxonomic and nomenclatorial suggestions............ 100 Geographic patterns of plesiomorph retention........ 102 Captions for figures.....................................105 Figures ............................................ 106 Tables....................................................109 Literature Cited......................................... 116 Appendices...................... 125 PART 3. Evolution of the genus Nerodia............................. 137 Introduction.................................... 138 Materials and Methods............ 139 iv Results.................................................. 142 Discussion............... 145 Captions for figures...................................... 156 Figures...................................................157 Tables............................. 161 Literature Cited......................................... 169 Appendices......................................